a) Field of the Invention
The present invention relates to a torsion damper, especially for a motor vehicle, such as is described and illustrated by way of example in the documents GB-A-2 219 647 and DE-U-79 26 142.
b) Description of Related Art
The damper described in GB-A-2 219 647 and DE-U-79 26 142 comprises a first rotating element and a second rotating element, which define between them an annular housing that receives a resilient damping means acting circumferentially between the two rotating elements.
It is desirable to lubricate the various components of the resilient damping means, and especially the springs that are comprised in such a damping means, together with their associated support zones formed on the rotating elements.
For that reason, it has been proposed in the above mentioned documents to seal the boundaries of the said annular housing so that it contains a lubricating agent, such as grease, which is unable to penetrate radially inwardly between the two rotating elements.
In order to ensure that the housing is sealed in the radially inward direction, the document DE-U-79 26 142 proposed sealing means which comprise two axial sealing rings, each of which is in engagement, through one of its surfaces, against a first support surface associated with the first rotating element, and through the other one of its surfaces against a second support surface associated with the second rotating element.
In the embodiment proposed in that document, each of the support surfaces is provided by an annular O-ring seal fitted in all annular groove, which is arranged for this purpose in a surface portion formed, in facing relationship, in each of the two rotating elements, while each sealing ring is retained radially by simple frictional contact of its opposed faces with the two corresponding O-ring seals.
More precisely, in the said document, the greater part of the annular housing is delimited by at least two components of a first one of the rotating elements, with the second rotating element comprising a disc which penetrates into the said housing.
Thus, one of the support surfaces is formed on the disc, with the said sealing rings being disposed on either side of the said disc.
The arrangement of the sealing means proposed in that document is particularly complex and expensive, in that it calls for a large number of components, in that it makes it necessary to carry out groove machining to precise dimensions for the O-ring seals, and in that assembly of the various components, in order to ensure correct positioning of the sealing rings between their corresponding seals, is particularly difficult to carry out and to automate.
In addition, the rings can evert, depending on manufacturing tolerances, especially in the O-ring seals.
Moreover, the above mentioned disc of the rotating element concerned has to have a not insignificant thickness so that the grooves can be formed. In this connection, the torque is transmitted through this disc, which must in consequence be of a predetermined thickness in order to transmit this torque. It is therefore necessary to take account of the grooves in order to determine this thickness.